Field of the Invention
The present invention relates to an image projection apparatus (projector).
Description of the Related Art
For a high-contrast projector, Japanese Patent No. 4,158,757 discloses a projector that: combines together a plurality of color light fluxes (i.e. light beams of different color) from a plurality of light modulation elements (image modulation elements); directs the combined light onto another light modulation element (luminance modulation element) to form an image thereon via an imaging optical system; and projects the image light (i.e. light from the image) modulated by the luminance modulation element onto a projection surface via a projection lens. A projector disclosed in Japanese Patent Laid-Open No. 2007-121693 modulates light from a light source through a luminance modulation element, chromatically separates luminance modulated light from the luminance modulation element, and forms an image on a plurality of image modulation elements through an imaging optical system. Then, the plurality of color light fluxes (light beams of different color) from the plurality of image modulation elements are combined together and projected as image light onto a projection surface via a projection lens.
However, the projector disclosed in Japanese Patent No. 4,158,757 needs an imaging optical system with an extremely high imaging performance so as to (i) maintain the resolution performance of the image light from the image modulation elements and (ii) modulate the luminance through the luminance modulation elements. On the other hand, in the projector disclosed in Japanese Patent Laid-Open No. 2007-121693, since the light with a higher intensity from the light source enters the luminance modulation element than that of each separated color light entering the image modulation element, the life of the luminance modulation element may be shorter than that of the image modulation element.